Read it here


"In my book Race Differences in Intelligence (2006, p.70), I estimated that sub-Saharan Africans have a phenotypic IQ of 67 and a genotypic IQ of 80. Thus, I estimated that the adverse environment reduces their IQ by 13 IQ points and that genetic factors reduce their IQ by 20 IQ points, compared with Europeans. Thus, 43 percent of the low IQ in sub-Saharan Africa is attributable to adverse environments and the remaining 57 percent is attributable to genetic factors."

http://www.npr.org/2011/10/31/141816...s-to-7-billion

"Population expert Joel Cohen points out that, in 1950, there were nearly three times as many Europeans as sub-Saharan Africans. If U.N. estimates are correct, there will be nearly five sub-Saharan Africans for every European by 2100."